In addition, this is an energy efficient issue.

That is entirely dependent upon the loads, distances, and routing.

I really enjoy taking Amtrak to DC and Baltimore and do it usually once a year if not twice.

"In Philadelphia, with an Amtrak ticket, back in the early 2000s at least, you could ride the suburban trains from 30th Street train station to Suburban Station or Market East (it didn't seem they checked anyone in that area, but I could be wrong) which was useful for seeing Independence Hall, etc... "

This is still true as I took advantage of it last year.